My talk at StringMath 2025, on BPS cohomology: BPS cohomology
A talk I gave at BIMSA (Beijing) in 2023, on cohomological DT theory old and new: ICBS talk
A talk I gave at the Sheffield WKB/BPS II conference on BPS cohomology and nonabelian Hodge theory: Sheffield talk
If you prefer video, here's a related talk, given in Birmingham (EAGLE vs COW)
A talk I gave at the IC Moduli zoominar on the decomposition theorem for stacks of objects in 2CY categories: slides video
A talk I gave at UCSD in 2020 on flopping curves and positivity of BPS invariants for finite-dimensional Jacobi algebras: UCSD talk
talk from the ICM satellite meeting on moduli spaces, specifically, on a "3d Goettsche-Soergel" theorem for Hilbert schemes: Campinas talk
A talk I gave at the Clay research conference in Oxford, 2017, on the definition of BPS invariants, their integrality, and Lie algebra structure: Clay talk
Notes for my course on BPS invariants at the summer school in Alpensia, South Korea: Cohomological DT theory course
A talk on the integrality conjecture and PBW bases at the MIT/Harvard AG seminar: Harvard talk
And here are notes from another talk on Yangians and the integrality conjecture, given at the Moduli Spaces conference in Tianjin, September 2015: Chern Institute talk
Some notes from another talk I gave in Warwick, this time on integrality of DT invariants for quivers: Integrality of DT invariants
A talk on scattering diagrams and theta functions I gave "in" Beijing in 2021: Beijing talk
A talk on scattering diagrams and strong quantum positivity I gave at UNAM, Mexico City: UNAM talk
A talk on the integrality conjecture and positivity in algebraic combinatorics I gave in Oxford: Oxford talk
Positivity for quantum cluster algebras - Strasbourg Quantum Algebra seminar: Strasbourg notes (handwritten, in French)
A talk on the integrality conjecture and positivity in algebraic combinatorics I gave in May 2016 in Oxford: Oxford talk
A fairly complete (2 hour talk) walkthrough of the proof of a joint result with Maulik, Schürmann and Szendrői regarding positivity and quantum cluster mutation that I gave in Paris: purity for quasihomogeneous potentials
A talk in Banff on joint work with Maulik, Schürmann and Szendrői on quantum cluster mutation and Hodge theory: Banff talk
Some proper typed notes from my Jan 2013 Lausanne talk on "Purity and positivity in DT theory": EPFL talk
Slides from a talk I gave on Okounkov's conjecture at EGEA II in Seoul in 2024: Talk
Notes from a lecture series on BPS Lie algebras and Yangians given at Northeastern University in 2024: Talk1, Talk2, Talk 3+4
A talk I gave on GKM algebras at Victor Kac's 80th birthday conference in Rome: Kac80
A talk on the affine Yangian of gl(1) and the CoHA of A^2 I gave in the M seminar: A2talk
A talk on fermionization of Hall algebras given at Bill Crawley-Boevey's 60th birthday conference: BCB60 talk
A longer talk on fermionization of Hall algebras that I gave at IPMU: Fermionization talk
A talk on corpoducts given in Oxford (2020): Oxford talk
A talk I gave at the Fields institute on Yangians: Fields talk
A talk on Borcherds algebras and Kac polynomials I gave in Notre Dame: CMND talk
A talk I gave on the passage from BPS state counting to Hall algebras for the workshop DAHA, Algèbres de Hall, Noeuds Toriques et Combinatoire: BPS->Hall
An introduction to Cohomological Hall algebras that I presented at EPFL, with some brief remarks about a recent new approach to the Kac conjecture: CoHAs from scratch
Notes from a talk I gave at Ezra Getzler's 60th birthday conference, on the decomposition theorem for 2CY categories and NAHT: Ezra talk
Notes from a minicourse I gave in the M seminar on a stacky nonabelian Hodge isomorphism and P=W conjecture: Talk 1 (video), Talk 2 (video), Talk 3 (video)
A talk I gave at the Perimeter Institute, on the definition of BPS Lie algebras, focusing on the special case of character varieties: Perimeter talk
Some notes from a talk I gave at the refined invariants workshop, Warwick University: Refined invariants/character varieties talk
A talk I gave in Pavia, relating critical cohomology that arises in the study of DT theory of real 3-manifolds to character varieties: Pavia talk
Another talk I gave in Pavia, this time concentrating on the links between CoHAs and character varieties Pavia talk May 2014
And then a more refined version, given at VBAC 2014 in Berlin: VBAC talk
And a fuller version of my VBAC 2014 talk, given in Seoul KIAS: VBAC+ talk